Can beautiful bands of wildflowers curb pesticide use?

Researchers hope that prettying up fields will attract beneficial bugs.

Common knapweed: Colorful and a magnet for aphid-eating insects.
(Photo: Dean Morley/flickr)

Enclosing farmland with rows of wildflowers isn’t exactly a new practice for farmers looking to boost biodiversity while putting a healthy dent in the amount of pesticides used on their crops.

Lining the perimeter of fields with pretty-as-can-be floral borders is a proven way to attract ground beetles, hoverflies and parasitic wasps — not the most lovable-sounding collection of arthropods, to be sure. However, these predatory insects do a solid job of keeping real pests such as aphids in check and, as a result, can help to lower a farm’s reliance on pesticides and increase crop yields. (Added bonus: they attract bees.)

But according to a recent report from the Guardian, ringing fields with wildflowers isn’t quite as effective as it could be considering that the beneficial bugs are only eliminating destructive pests on the outskirts of fields and not toward the center, where there’s an even greater abundance of crop-damaging free meals for the taking. After all, why would a perfectly content bug travel out of its way for an tasty aphid snack when it doesn’t really have to?

"If you imagine the size of a [ground beetle], it’s a bloody long walk to the middle of a field," explains Richard Pywell of England’s Centre for Ecology and Hydrology (CEH).

And so, Pywell and his colleagues have launched a literal field study that’s more or less a no-brainer when it comes to broadening the range of pest-munching predatory insects: extending the rows of wildflowers inside the fields, in lieu of simply limiting bug-attracting blooms to the periphery. The brightly colored floral strips planted as part of a five-year test-run at 15 farms across eastern and southern England are only six meters (a little under 20 feet) wide. The strips take up a mere smidge — roughly 2 percent — of valuable cropland when spaced about 100 meters (328 part), a distance that allows for pest-eradicating insects to better infiltrate the fields and do what they do best.

For the study, farmers planted strips of red clover, oxeye daisy, wild carrot and the purple-hued nectar machine known as common knapweed.

Per the Guardian, the strips "will be monitored through a full rotation cycle from winter wheat to oil seed rape to spring barley." And because modern farm equipment is increasingly GPS-guided, farmers can now easily work around the elongated wildflower strips, whereas once upon a time they would have been a major encumbrance.

One possible drawback that researchers will be on the lookout for is the effect that planting wildflowers near where pesticides are directly sprayed might have on beneficial bugs drawn to the center of fields — it’s obviously a sensitive balance. But Plywell hopes the pros in this instance outweigh the cons. That being said, the wildflower strips are being viewed as more of a viable complement to common pest-control methods such as spraying rather than a full replacement. The goal, for now at least, is a sizable reduction in usage, not a full-on stop (although one can dream, considering the detrimental impact that the unchecked use of chemical pesticides can have on beneficial wildlife and human health).

The United Kingdom did make significant progress on this front in November 2017 when environment minister Michael Gove vowed to support a total ban on neonicotinoids, a widely used class of agricultural pesticides linked to the alarming decline of bee populations across Europe. While the U.K. previously did not support such a ban, Gove believes that more recent evidence of the harm posed by neonicotinoids to crucial pollinators warranted this much-welcomed shift in thinking.

"The weight of evidence now shows the risks neonicotinoids pose to our environment, particularly to the bees and other pollinators which play such a key part in our £100bn food industry, is greater than previously understood," said Gove. "I believe this justifies further restrictions on their use. We cannot afford to put our pollinator populations at risk."

Wildflower strip pest-control studies similar to the ones headed by the CEH in England have also been conducted in Switzerland using cornflowers, buckwheat, dill, coriander and poppy, and the results have been similarly promising.